Three dimensional (3D) printing is a new type quick molding manufacturing technology, which is based on a three dimensional model designed by a computer. It stacks and bonds special materials such as metal powder, ceramic powder, plastic and cell tissues layer by layer by means of a software layered discrete and numerical control molding system to finally achieve stack molding, so as to obtain an entity product. It can overcome the special structural barriers that cannot be achieved by the conventional mechanical processing, and carry out simple production of complex structural members.
At present, the 3D printing technology mainly includes heat melt plastic base technology, laser sintering molding technology, light curable liquid resin selective area curing molding technology, etc. The light curing method performs material accumulation for molding by using the principle that the light curable material is cured after being irradiated by light.
The existing imaging system for the 3D printing device generally cures the light curable material using a liquid crystal panel. As schematically shown in FIG. 1, the conventional imaging system comprises a light source system 1 as a backlight and a liquid crystal screen 2. The two sides of the liquid crystal screen 2 are further respectively provided with polarizers 201, 202. The light emitted by the liquid crystal screen 2 is projected on a surface 3 of the light curable material so as to enable the light curable material to be cured. Generally, the polarizers 201, 202 would absorb the light emitted by the light source system 1 greatly, causing a low utilization ratio for the light emitted by the light source system 1 and a high power consumption of the whole system. In addition, long term near ultraviolet irradiation would accelerate aging of the liquid crystal material, thereby influencing the life time of the 3D printing device.